Re: Rx Radio #ubitx-help

Ralph Mowery

While most AM is set up for a 6 KHz of audio, a side band filter of slightly over 2 KHz will usually allow voice through well enough to be understood.  The music will sound clipped or somewhat distorted as it often has higher audio frequencies than  most taking voices.

The filter in most of the ubitx is really too narrow to suit me as I only operate ssb with it.  I changed out the 5  100pf capacitors in the crystal filter to 82 pf ( I think that is the standard value).  That broadened the filter in my ubitx from about 1700 hz to about 2300 hz.  Makes the audio sound much better for me.

One thing not discussed is that while AM often has the 6 khz filter, it only needs to be about half that when using a ssb filter as you are only using one sideband instead of both .  So around 3 khz would be good for AM.

de ku4pt

On Fri, Jun 22, 2018 at 3:50 PM, sridhar <vu3pen@...> wrote:

thx for tech inputs , yes i got the details from this post 
AM allows for 5KHz of audio and SSB allows for roughly 2.7 to 3 KHz of audio
to change this filters required 


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